Mandibular class i situation/endodontic courses

Essentials of partial
denture design
INDIAN DENTAL ACADEMY
Leader in continuing Dental Education
www.indiandentalacademy.com

Classes I & II
• 1. Direct retention
a. The main objective should be restoration of
the function and appearance and the
maintanance of comfort, with great
emphasis on preservaion of the health and
integrity of all the oral structures that remain

b. Close adaptation and proper contour of an
adequately extended denture base and
accurate fit of the framework against multiple,
prepared guide planes should be used to help
the retentive clasp arms retain the prosthesis.

• 2. clasps
a. simplest type of clasp should be used
b. clasp should have a good stabilizing
quality, remain passive until activated by
functional stress.

Clasps in class I prosthesis
• Requires only two retentive clasps, one on
each side.
– If a distobuccal undercut is present, the
vertical projection retentive clasp is preferred.
– If mesiobuccal undercut is present, wrought
wire clasp is indicated. A cast circumferential
clasp should not be used.
– The reciprocal or bracing arm must be rigid.

Clasps in class II prosthesis
• Usually there are three retntive clasps
– The distal extension side should be designed
with the same considerations as for a class I
prosthesis
– The tooth supported or modification side,
should have two retentive clasp arms, one as
far posterior and one far as anterior.

• 3. rests
a. rests seats should be prepared so that
stress will be directed along the long axis
of the teeth
b. rests should be placed next to the
edentulous space.

• 4. indirect retention
a. should be located as far anterior to the
fulcrum line as possible
b. two indirect retainers should be used for
class I prosthesis, but one indirect retainer
can be used on the side opposite the
edentulous space in a class II design

• C. should be placed in properly prepared
rest seats so that forces will be directed
along the long axis of the teeth
• Lingual plating can also be used as an
effect indirect retainer.

• Major connector
– Should be rigid
– Not impinge on the gingival tissues
– Support from the hard palate should be used
in design of the maxillary major connector
– Can be extended onto the lingual surfaces of
the tooth to increase rigidity, distribute lateral
forces, improve indirect retention, and
eliminate food impaction

Mandibular class I situation

Rests Guide plates

Mandibular class II situation

Class III design

• 1. direct retention
– Clasps
– Quadrilateral type of positioning of direct
retainers is ideal
– Tooth and tissue contours should be
considered when selecting a clasp
– Bracing arm must be rigid

• 2. rests
– Rest seat should be prepared next to the
edentulous space when possible
– Should be used to support the major
connector and lingual plating

Mandibular class III situation

Mandibular class IV situation

Maxillary class I situation

Maxillary class II design

Maxillary class III design

Maxillary class IV design

summary
• When providing a partial denture service,
it may be divided into three phases. The
planning phase, the preparing of the
mouth, and the designing of the partial
denture.
• A tentataive design should be worked out
in the planning phase, and the necessary
extractions, restorations, and modification
of the tooth contours planned.

• When the preparatory phase is complete, the
master casts are made and the designs are
made on the master casts.
• Partial denture must be designed with
consideration for forces exerted in function, and
for the effects of these forces on the health of
the remaining teeth. The partial denture must be
designed to minimize the occlusal forces, to
butress the remaining teeth against especially
destructive lateral forces.

conclusion
When designing a partial denture the following
considerations should be met
- Provide adequate support on the remaining
natural teeth to resist vertical stresses, and to
direct those stresses in the direction of the long
axis of the abutment teeth.
- Provide a broad coverage of saddle areas, so
that stress are distributed over a broad area

- Provide adequate tooth borne resistance
to lateral stresses
- Provide adequate retention
- Have rigid bars and connectors
- Decrease the occlusal table by narrowing
artificial teeth
- Placing the denture teeth over the ridge
- Avoid covering the free gingival margin

References
• An atlas of removable partial denture
design – Russell J Stratton
• Clinical removable partial prosthodontics –
stewart
• Essential of removable partial denture
prosthodontics – oliver c applegate
• Prosthodontic treatment for partially
edentulous patients – george a zarb

• Planning and desiging removable partial
dentures – arthur H Schmidt – JPD 1953,
pg 783-806
• Physilogic approach to partial denture
design – Ellsworth K Kelly – JPD 1953 –
pg 699 - 710

Mandibular class i situation/endodontic courses

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